The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Samaneh Abbasi , Abdelsalim Derdouri , Pierre J. Carreau, May 2010
We have studied the properties of MWCNT composites based on a polypropylene (semi-crystalline) and a polycarbonate (amorphous) matrix. Nanocomposites were prepared under different mixing conditions by diluting highly concentrated masterbatches. To promote nanotube dispersion in polypropylene nanocomposites and in order to investigate the effect of dispersion level on the properties of nanocomposites, different types of maleic anhydride grafted polypropylene were used including Polybond PB3150, Polybond PB3002 and Epolene E43. The state of dispersion was further analyzed by Scanning Electron Microscopy (SEM). The electrical percolation threshold of the PP/MWCNT composites is somehow less than that of the PC composites; however, the percolation threshold and the conductivity level above the threshold are completely dependent on nanotube dispersion in nanocomposite. Based on DSC results, the crystallinity of PP/MWCNT samples increases with the MWCNT content.
Lilac Cuiling Wang , Siu N. Leung , Chul B. Park , Markus Bussmann, May 2010
Pressure is a critical parameter that affects the degree of supersaturation within a polymer-gas solution when foaming. In most previous studies on cell nucleation, a uniform pressure throughout the solution was assumed. Although this assumption may be acceptable when no nucleating agent has been added, its validity is questionable when nucleating agents are present. The discontinuity at the interface between the nucleating agent and surrounding material is a potential heterogeneous nucleation site, and so the stress field around a particle will be different from the bulk. In light of this, this paper presents a numerical analysis to investigate the pressure profile around cell nucleating agents. Such an investigation is expected to provide new insights to understand cell nucleation phenomena.
Innovative electrospinning techniques were explored to facilitate the production of large electrospun silk mats for applications related to wound dressings. Limitations experienced producing experimental grade materials were attributed to the intermittent polymer spray inherent in the electrospinning process. Applying fundamental electrodynamics, electrostatic field gradients generated at alternative equipotential node points on a modified potential plate were shown to stably displace and orient the spinning fiber on specific vector beyond the material damaging spray zone. High speed photography and electrostatic field gradient simulation verified a sixteen degree angular displacement of the electrified fluid jet as the equipotential was repositioned from the center to the edge of a disk shaped potential plate. Additionally, the symmetrical displacement signature around the potential plate enabled concurrent multi-spinning with one commercial apparatus. This novel electrospinning approach provides the ability to create large experimental grade electrospun silk materials suitable for biocompatibility assessments related to wound dressings and establishes manufacturing standards by which electrospun silk materials may be commercially produced.
The effect of panel thickness on impact properties of ionomers, which exhibit self-healing properties, was investigated for the purpose of determining the critical thickness that is required to observe self-healing behavior upon impact of various ionomers and the unionized base resin. Self-healing closure of the impact damage zones occurred in a panel thickness range of 5.5 ƒ?? 6.0 mm and greater for all ionomers as well as the unionized base resin investigated regardless of phase morphology, counter-ion used for neutralization, and the percent neutralization of the ethylene-methacrylic acid copolymer (EMAA) base resin. Furthermore, with an increase in panel thickness there was an increase in impact energy absorbed, however, the slope of the curve shifts at a panel thickness of 0.9 mm and 8.5 mm. The shift in slope is attributed to a shift from brittle to ductile failure and a larger to smaller overall damage zone, respectively.
Many consumer products have a complex construction with multiple types of materials. This makes it difficult to recycle the products if the materials are not easily separated. A mixed recycling study was conducted for a particular multi-material product to determine the degree of material segregation required to obtain a recycled feedstock with useful properties. Toothbrushes were selected as the product for this study. These were collected from a commercial take-back program and were separated by material. Different formulations were compounded with virgin material at varying percentages and molded into ASTM test specimens for mechanical property testing.
At Antec 2008, a new single screw compounder (SSE) was introduced with newly designed mixers along the screw. These mixing elements had spiral flutes with elongational mixing (SFEM). The Elongator, hereafter SFEM, demonstrated simple processing of RPVC powder with an increased output from the historic limit of 30 rpm to a faster speed of 180 rpm at only 174 ?øC, vented, starved or flood fed. There was no need for a vacuum hopper or crammer feeder with this simple screw design.This paper presents scale up work that was performed on a 2.5' extruder with the RPVC powder. The new SSE processed RPVC powder with an increase in screw speed to 70 rpm and output temperature of only 191 ?øC, nonvented, with screw cooling, and flood feeding.This paper also presents mixing tests performed with the smaller SSE using a newly designed SFEM (hereafter SFEM-II). Two tests were performed with the RPVC powder, one using 0.5% color concentrate and the other wood flour.
Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) are two major thermal analysis techniques which can be used for failure analysis of polymers and composites. DSC and TGA offer wealth of in-depth information related to the composition, processing, structure, and properties of the materials. Important thermodynamic and kinetic parameters that determine the performance and properties of products, such as glass transition temperature, melting and crystallization, crystallinity, degree of cure, thermo-oxidative stability, and material composition, can be obtained through carefully designed experiments using individual or combined testing of DSC and TGA.
Sunny M. Ogbomo, Divya Kosuri, Nandika A. D’Souza, May 2010
The discovery of Olefin Block Copolymers (OBC) brought opportunities to develop novel soft compounds for the consumer durables market. These new soft compounds are primarily blends that include a rigid polymer, a rubber, and an oil. This work was aimed at developing fundamental understanding on morphology development of OBC/PP/Oil blends at two different oil levels. The results showed that mechanical properties are dominated by the development of two phase morphologies at low and high rubber volume fractions. A dynamic mechanical analysis at low strains showed that the storage modulus behavior at high rubber volume fractions could be explained with known composite models.
Traditionally, the mold qualification procedure involves sampling the mold and establishing a process to make acceptable parts. Process engineering studies such as in-mold rheology, gate seal tests and generating process windows are most commonly performed. Design of Experiments (DOE) are conducted to study the effect of the molding factors on the quality of the part and sometimes to find the process to mold a part within the quality specifications. The process engineering studies and the DOEs are conducted independent of each other. This paper combines these techniques and introduces the concepts of the Aesthetic Process Window, the Dimensional Process Window and the Control Process Window.
The heterogeneous nucleation behavior of block copolymer polypropylene modified with fine talc is discussed as a function of talc fineness and loading into a polymer matrix. Specifically, three talc samples having different particle size distributions were used to modify the resin. Non isothermal and isothermal nucleation were studied and mechanical performances were evaluated as well. Itƒ??s been demonstrated that higher nucleation efficiency can be observed for the finer talc sample at the higher concentration (evaluated in experimental work). Isothermal crystallization study showed on one side a visible reduction of crystallization half time when talc is introduced in block copolymer polypropylene and kinetic parameters from Avrami models on isothermal tests confirmed efficiency of talc as nucleating agent. Besides process advantages in nucleating block copolymer polypropylene (lower cycle time in injection molding), an evident advantage in mechanical properties was observed. The addition of talc in small amount enhanced rigidity and lowered molding shrinkage, with no significant variation in impact resistance properties.
Wolfgang Abele , Yukihito Ozaki , Takeshi Chiba , Kazunori Saegusa, May 2010
Kaneka Corporation has developed a silicone based flame retardant for Polycarbonate, Kane Ace MR-01. MR- 01 realizes non-bromine and non-phosphorus flame retardant PC compound and increases low-temperature impact strength. Kaneka's renowned graft polymerization technology makes it possible to disperse the cross-linked silicone particle into Polycarbonate matrix. MR-01 achieves V-0 in UL-94 protocol at 1.2 mm thickness (Kaneka's evaluation data) with a small amount of PTFE. MR-01 also has excellent thermal stability, which provides with superior impact strength retention after heat aging, and maintains the flame retardancy after recycling process.
The current range of products designed to attain special effects continues to expand. Growth was driven by designers demanding new options to color plastic parts. Producers of effect pigments continue to respond with technological innovations and modifications of existing pigments and additives. This paper will discuss this expanded pallet and the effects and applications for which they were intended. The primary focus is on Industrial grade pearlescent pigments, synthetic grade pearlescent pigments (including colored pigment coated pearls), high density coated pearl pigments and novel metal oxide coated pearlescent pigments.
This paper describes new materials and applications for the plastics industry focused on lasermarking polymers. In the context of the paper we will describe the current state of-the-art, equipment and the new technology.
Laser marking is generally accepted to be the best way of permanently marking plastics. As a leader in laser marking Technology, we offers laser marking additives which improve the laser sensitivity of polymers. In addition to the standard portfolio (we will call them ƒ??Lƒ?products); we have added an outstanding NEW laser additive (we will call this product line ƒ??Mƒ? products): it is a robust, high-performance additive that enhances the dark-on-lightƒ? laser marking performance of most thermoplastics. Its versatility makes it suitable for use in all processing technologies and for a wide range of applications. The pelletized product ƒ??Mƒ?? can be added directly in the processing step or incorporated in masterbatches together with other additives and colors.
Expanded graphite (EG)-filled epoxy composites with thermal conductivity of 56 W/m-k were developed for applications as bipolar plates in proton exchange membrane (PEM) fuel cells. The high thermal conductivity resulted from the high intrinsic thermal conductivity of EG of 600 W/m-k. The global conductive network of graphite in the composites was achieved via solution intercalation mixing followed by compression molding and curing process. Characterization of surface chemistry of the EG by XPS showed strong potential for interfacial adhesion between graphite and epoxy matrix, which in the final composites resulted in reduced interfacial thermal boundary resistance, and thus high thermal conductivity.The composites also showed high electrical conductivity of 200-500 S/cm.
Nan Chen, Jing Wang, Yaogai G. Li, Takashi Kuboki, Chul B. Park, May 2010
This paper describes new materials and applications for the plastics industry focused on lasermarking polymers. In the context of the paper we will describe the current state of-the-art, equipment and the new technology.
Laser marking is generally accepted to be the best way of permanently marking plastics. As a leader in laser marking Technology, we offers laser marking additives which improve the laser sensitivity of polymers. In addition to the standard portfolio (we will call them ƒ??Lƒ? products); we have added an outstanding NEW laser additive (we will call this product line ƒ??Mƒ? products): it is a robust, high-performance additive that enhances the dark-on-lightƒ? laser marking performance of most thermoplastics. Its versatility makes it suitable for use in all processing technologies and for a wide range of applications. The pelletized product ƒ??Mƒ? can be added directly in the processing step or incorporated in masterbatches together with other additives and colors.
Nan Chen , Jing Wang , Yaogai G. Li , Takashi Kuboki , Chul B. Park, May 2010
In this paper, the effect of a dissolved blowing agent on the flow rate in extrusion and injection molding is studied using a single-screw foaming extruder with an accurate gas injection control. Although the decrease of the viscosity with the dissolution of the blowing agent has been measured and modeled, the flow properties have not been quantitatively evaluated to determine the processing window in foam extrusion and injection molding. This research measures the flow rate change systematically with varying the gas content in the polymer melt while maintaining the pressure constant by controlling the gear pump speed. The reduced viscosity increased the mass flow rate of the polymer significantly despite the decreased density with the dissolution of gas.
When it comes to resin drying, energy consumption is quickly becoming a key factor in the decision making process for one technology over another. However, drying energy consumption has several elements and key factors that affect the overall energy use of a dryer. It is a combination of heat-up energy and sustainable drying energy that are the elements that will, in the end, affect how much it costs to dry your resin on an annual basis.A uniform industry test standard would define the air capacity, basic load and kWh/unit of material. An industry test standard would allow users to plug in there given material, throughput and local energy rate, to calculate the true annual energy cost.
Conventional coextrusion and lamination
technologies were employed to characterize layer
sequencing effects on the impact properties of
multilayered, transparent structures incorporating high
impact resistant materials. Laminated structures utilizing
100 sheets of five-layered coextruded films were
successfully generated. Cross-sectional specimens of
these structures revealed no obvious weld lines. Most
importantly, layer sequencing had a distinct influence on
the impact failure modes and, therefore, on the impact
properties of the thick multilayered structures.
This work studies the use of surface bonded piezoelectric
induced strain actuators and their effect on the static
deflection of a single lap joint epoxy-fiber composite
cantilever beam. Euler-Bernoulli beam theory was utilized
to derive the elastic curves for pre-load and post-load
actuation, accounting for changes in flexural rigidity of
the beam. The model accounts for physical properties of
the composite beam and piezoelectric, as well as the
piezoelectric bond location. A numerical study aimed at
evaluating the effectiveness of piezoelectric actuation
based pre-load and post-load actuation, as well as bond
region has been performed. Post-load actuation was found
to be from 2.5% - 70% more effective than pre-load
actuation, depending on the bond location. Bond Region I
was found to be most effective for both pre-load and postload
actuation.
Jongeun Ryu , Tsuyoshi Saotome , H. Thomas Hahn, May 2010
In this paper, mediator-, separator-less glucose/O2 biofuel cell was built on carbon nanotube (CNT) mat electrodes. Glucose oxidase (GOx) and bilirubin oxidase (BOD) were immobilized on the mat via covalent bonding. The CNT mat is a sheet of multi-walled carbon nanotubes (MWNTs) which has high electrical conductivity and aspect ratio. CNT mat is expected to be one of the ideal electrode materials for biochemical applications for its easy functionalization, electrical conductivity, large surface area, porosity, and ability to lower the overpotential in various bio-chemical species. The electron transfer rate constant obtained in this study is 1.78 s-1. The open circuit voltage and maximum power density obtained from this biofuel cell are 50 mV and 38.7 ?¬A/cm2, respectively.
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Any article that is cited in another manuscript or other work is required to use the correct reference style. Below is an example of the reference style for SPE articles:
Brown, H. L. and Jones, D. H. 2016, May.
"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.
Note: if there are more than three authors you may use the first author's name and et al. EG Brown, H. L. et al.